It's actually not a problem with the router. I have this sometimes and normally it's when I'm trying to log directly from a technic server to Skyblock. If this ever occurs again try logging in again or restarting your game.
Well, the main cause of this is Mojang. Their authentication servers or simply just multiplayer, sometimes goes down. Apparently, in your case, it's your router. Never seen problems from the router, but good to keep that in mind. Can this be locked?
Thread Locked on request. If you disagree to this action, please report this post, and a moderator or administrator will reconsider it. Kind regards, The Staff
